Biosynthesis of the Azoxy Compound Azodyrecin from Streptomyces mirabilis P8-A2

Azoxy compounds are a distinctive group of bioactive secondary metabolites characterized by a unique RN═N+(O-)R moiety. The azoxy moiety is present in various classes of metabolites that exhibit various biological activities. The enzymatic mechanisms underlying azoxy bond formation remain enigmatic. Azodyrecins are cytotoxic azoxy metabolites produced by Streptomyces mirabilis P8-A2. Here, we cloned and confirmed the putative azd biosynthetic gene cluster through CATCH cloning followed by expression and production of azodyrecins in two heterologous hosts, S. albidoflavus J1074 and S. coelicolor M1146, respectively. We explored the function of 14 enzymes in azodyrecin biosynthesis through gene knockout using CRISPR-Cas9 base editing in the native producer, S. mirabilis P8-A2. The key intermediates were analyzed in the mutants through MS/MS fragmentation studies, revealing azoxy bond formation via the conversion of hydrazine to an azo compound followed by further oxygenation. Enzymes involved in modifications of the precursor could be postulated based on their predicted function and the intermediates identified in the knockout strains. Moreover, the distribution of the azoxy biosynthetic gene clusters across Streptomyces spp. genomes is explored, highlighting the presence of these clusters in over 20% of the Streptomyces spp. genomes and revealing that azoxymycin and valanimycin are scarce, while azodyrecin and KA57A-like clusters are widely distributed across the phylogenetic tree.

Detection of chromosomal aneuploidy in ancient genomes

Ancient DNA is a valuable tool for investigating genetic and evolutionary history that can also provide detailed profiles of the lives of ancient individuals. In this study, we develop a generalised computational approach to detect aneuploidies (atypical autosomal and sex chromosome karyotypes) in the ancient genetic record and distinguish such karyotypes from contamination. We confirm that aneuploidies can be detected even in low-coverage genomes ( ~ 0.0001-fold), common in ancient DNA. We apply this method to ancient skeletal remains from Britain to document the first instance of mosaic Turner syndrome (45,X0/46,XX) in the ancient genetic record in an Iron Age individual sequenced to average 9-fold coverage, the earliest known incidence of an individual with a 47,XYY karyotype from the Early Medieval period, as well as individuals with Klinefelter (47,XXY) and Down syndrome (47,XY, + 21). Overall, our approach provides an accessible and automated framework allowing for the detection of individuals with aneuploidies, which extends previous binary approaches. This tool can facilitate the interpretation of burial context and living conditions, as well as elucidate past perceptions of biological sex and people with diverse biological traits.

An individual with Sarmatian-related ancestry in Roman Britain

In the second century CE the Roman Empire had increasing contact with Sarmatians, nomadic Iranian speakers occupying an area stretching from the Pontic-Caspian steppe to the Carpathian mountains, both in the Caucasus and in the Danubian borders of the empire.1,2,3 In 175 CE, following their defeat in the Marcomannic Wars, emperor Marcus Aurelius drafted Sarmatian cavalry into Roman legions and deployed 5,500 Sarmatian soldiers to Britain, as recorded by contemporary historian Cassius Dio.4,5 Little is known about where the Sarmatian cavalry were stationed, and no individuals connected with this historically attested event have been identified to date, leaving its impact on Britain largely unknown. Here we document Caucasus- and Sarmatian-related ancestry in the whole genome of a Roman-period individual (126-228 calibrated [cal.] CE)-an outlier without traceable ancestry related to local populations in Britain-recovered from a farmstead site in present-day Cambridgeshire, UK. Stable isotopes support a life history of mobility during childhood. Although several scenarios are possible, the historical deployment of Sarmatians to Britain provides a parsimonious explanation for this individual's extraordinary life history. Regardless of the factors behind his migrations, these results highlight how long-range mobility facilitated by the Roman Empire impacted provincial locations outside of urban centers.

Comparative verification of control methodology for robotic interventional neuroradiology procedures

PURPOSE

The use of robotics is emerging for performing interventional radiology procedures. Robots in interventional radiology are typically controlled using button presses and joystick movements. This study identified how different human-robot interfaces affect endovascular surgical performance using interventional radiology simulations.

METHODS

Nine participants performed a navigation task on an interventional radiology simulator with three different human-computer interfaces. Using Simulation Open Framework Architecture we developed a simulation profile of vessels, catheters and guidewires. We designed and manufactured a bespoke haptic interventional radiology controller for robotic systems to control the simulation. Metrics including time taken for navigation, number of incorrect catheterisations, number of catheter and guidewire prolapses and forces applied to vessel walls were measured and used to characterise the interfaces. Finally, participants responded to a questionnaire to evaluate the perception of the controllers.

RESULTS

Time taken for navigation, number of incorrect catheterisations and the number of catheter and guidewire prolapses, showed that the device-mimicking controller is better suited for controlling interventional neuroradiology procedures over joystick control approaches. Qualitative metrics also showed that interventional radiologists prefer a device-mimicking controller approach over a joystick approach.

CONCLUSION

Of the four metrics used to compare and contrast the human-robot interfaces, three conclusively showed that a device-mimicking controller was better suited for controlling interventional neuroradiology robotics.

Advanced MR Techniques for Preoperative Glioma Characterization: Part 2

Preoperative clinical MRI protocols for gliomas, brain tumors with dismal outcomes due to their infiltrative properties, still rely on conventional structural MRI, which does not deliver information on tumor genotype and is limited in the delineation of diffuse gliomas. The GliMR COST action wants to raise awareness about the state of the art of advanced MRI techniques in gliomas and their possible clinical translation. This review describes current methods, limits, and applications of advanced MRI for the preoperative assessment of glioma, summarizing the level of clinical validation of different techniques. In this second part, we review magnetic resonance spectroscopy (MRS), chemical exchange saturation transfer (CEST), susceptibility-weighted imaging (SWI), MRI-PET, MR elastography (MRE), and MR-based radiomics applications. The first part of this review addresses dynamic susceptibility contrast (DSC) and dynamic contrast-enhanced (DCE) MRI, arterial spin labeling (ASL), diffusion-weighted MRI, vessel imaging, and magnetic resonance fingerprinting (MRF). EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 2.

Advanced MR Techniques for Preoperative Glioma Characterization: Part 1

Preoperative clinical magnetic resonance imaging (MRI) protocols for gliomas, brain tumors with dismal outcomes due to their infiltrative properties, still rely on conventional structural MRI, which does not deliver information on tumor genotype and is limited in the delineation of diffuse gliomas. The GliMR COST action wants to raise awareness about the state of the art of advanced MRI techniques in gliomas and their possible clinical translation or lack thereof. This review describes current methods, limits, and applications of advanced MRI for the preoperative assessment of glioma, summarizing the level of clinical validation of different techniques. In this first part, we discuss dynamic susceptibility contrast and dynamic contrast-enhanced MRI, arterial spin labeling, diffusion-weighted MRI, vessel imaging, and magnetic resonance fingerprinting. The second part of this review addresses magnetic resonance spectroscopy, chemical exchange saturation transfer, susceptibility-weighted imaging, MRI-PET, MR elastography, and MR-based radiomics applications. Evidence Level: 3 Technical Efficacy: Stage 2.

Yersinia pestis genomes reveal plague in Britain 4000 years ago

Extinct lineages of Yersinia pestis, the causative agent of the plague, have been identified in several individuals from Eurasia between 5000 and 2500 years before present (BP). One of these, termed the 'LNBA lineage' (Late Neolithic and Bronze Age), has been suggested to have spread into Europe with human groups expanding from the Eurasian steppe. Here, we show that the LNBA plague was spread to Europe's northwestern periphery by sequencing three Yersinia pestis genomes from Britain, all dating to ~4000 cal BP. Two individuals were from an unusual mass burial context in Charterhouse Warren, Somerset, and one individual was from a single burial under a ring cairn monument in Levens, Cumbria. To our knowledge, this represents the earliest evidence of LNBA plague in Britain documented to date. All three British Yersinia pestis genomes belong to a sublineage previously observed in Bronze Age individuals from Central Europe that had lost the putative virulence factor yapC. This sublineage is later found in Eastern Asia ~3200 cal BP. While the severity of the disease is currently unclear, the wide geographic distribution within a few centuries suggests substantial transmissibility.

On Natural History and Management of Colloid Cysts: Time to Rethink?

BACKGROUND

Colloid cysts, although benign, may occasionally cause obstructive hydrocephalus and sudden death. Reliable prognostic factors for symptomatic progression have been sought, with heterogenous results.

METHODS

We conducted a retrospective review of all cases of colloid cysts of the third ventricle managed at our center between 2009 and 2019. Clinical and neuroimaging characteristics were analyzed using logistic regression in relation to symptomatic status and hydrocephalus. The cutoff values for outcome prediction were calculated using the receiver operating characteristic curve analysis.

RESULTS

There were 82 patients with colloid cysts, of whom 60 were asymptomatic and 22 symptomatic. None of the asymptomatic patients experienced acute neurologic decline or hydrocephalus during follow-up, whereas half (n = 11) of the symptomatic patients presented with hydrocephalus, 8 of whom had acute hydrocephalus. We found 3 putative candidate risk factors for symptomatic colloid cysts: T1-weighted magnetic resonance imaging hyperintense/mixed signal appearance (P = 0.004), location in risk zone I (P = 0.007), and a volume >236.49 mm³ (P = 0.007). Cyst diameter and volume/foramen of Monro diameter ratios had a decreasing trend over time among asymptomatic patients, providing new insights into the natural history of the disease.

CONCLUSIONS

Only a few asymptomatic colloid cysts showed progression requiring surgery, with no acute deterioration or fatal events, whereas the rest remained stable over time, thus supporting a more conservative approach for this group of patients. Higher risk for developing symptomatic colloid cyst was defined by a risk score that included T1-weighted magnetic resonance imaging appearance, risk zone, and colloid cyst volume, aiding the detection of patients at risk of clinical deterioration.

Machine-learning algorithm in acute stroke: real-world experience

AIM

To assess the clinical performance of a commercially available machine learning (ML) algorithm in acute stroke.

MATERIALS AND METHODS

CT and CT angiography (CTA) studies of 104 consecutive patients (43 females, age range 19-93, median age 62) performed for suspected acute stroke at a single tertiary institution with real-time ML software analysis (RAPID™ ASPECTS and CTA) were included. Studies were retrospectively reviewed independently by two neuroradiologists in a blinded manner.

RESULTS

The cohort included 24 acute infarcts and 16 large vessel occlusions (LVO). RAPID™ ASPECTS interpretation demonstrated high sensitivity (87.5%) and NPV (87.5%) but very poor specificity (30.9%) and PPV (30.9%) for detection of acute ischaemic parenchymal changes. There was a high percentage of false positives (51.1%). In cases of proven LVO, RAPID™ ASPECTS showed good correlation with neuroradiologists' blinded independent interpretation, Pearson correlation coefficient = 0.96 (both readers), 0.63 (RAPID™ vs reader 1), 0.69 (RAPID™ vs reader 2). RAPID™ CTA interpretation demonstrated high sensitivity (92.3%), specificity (85.3%), and negative predictive (NPV) (98.5%) with moderate positive predictive value (PPV) (52.2%) for detection of LVO (N=13). False positives accounted for 12.5% of cases, of which 27.3% were attributed to arterial stenosis.

CONCLUSION

RAPID™ CTA was robust and reliable in detection of LVO. Although demonstrating high sensitivity and NPV, RAPID™ ASPECTS interpretation was associated with a high number of false positives, which decreased clinicians' confidence in the algorithm. However, in cases of proven LVO, RAPID™ ASPECTS performed well and had good correlation with neuroradiologists' blinded interpretation.

NIMG-67. MULTI-PARAMETRIC MRI-BASED MACHINE LEARNING ANALYSIS FOR PREDICTION OF NEOPLASTIC INFILTRATION AND RECURRENCE IN PATIENTS WITH GLIOBLASTOMA: UPDATES FROM THE MULTI-INSTITUTIONAL RESPOND CONSORTIUM

PURPOSE

Glioblastoma is extremely infiltrative with malignant cells extending beyond the enhancing rim where recurrence inevitably occurs, despite aggressive multimodal therapy. We hypothesize that important characteristics of peritumoral tissue heterogeneity captured and analyzed by multi-parametric MRI and artificial intelligence (AI) methods are generalizable in the updated multi-institutional ReSPOND (Radiomics Signatures for PrecisiON Diagnostics) consortium and predictive of neoplastic infiltration and future recurrence.

METHODS

We used the most recent update of the ReSPOND consortium to evaluate and further refine generalizability of our methods with different scanners and acquisition settings. 179 de novo glioblastoma patients with available T1, T1Gd, T2, T2-FLAIR, and ADC sequences at pre-resection baseline and after complete resection with subsequent pathology-confirmed recurrence were included. To establish generalizability of the predictive models, training and testing of the refined AI model was performed through Leave-One-Institution-Out-Cross-Validation schema. The multi-institutional cohort consisted of the Hospital of the University of Pennsylvania (UPenn, 124), Case Western Reserve University/University Hospitals (CWRU/UH, 27), New York University (NYU, 13), Ohio State University (OSU, 13), and University Hospital Río Hortega (RH, 2). Features extracted from pre-resection MRI were used to build the model predicting the spatial pattern of subsequent tumor recurrence. These predictions were evaluated against regions of pathology-confirmed post-resection recurrence.

RESULTS

Our model predicted the locations that later harbored tumor recurrence with overall odds ratio (99% CI)/AUC (99% CI), 12.0(11.8-12.2)/0.80(0.76-0.85), and per institute, CWRU/UH, 11.0(10.7-11.3)/0.80 (0.64-0.97); NYU, 7.0(6.7-7.3)/0.78(0.56-1.00); OSU, 18.3(17.5-19.1)/0.83(0.54-1.00); RH, 40.0(35.3-45.5)/0.93(0.00-1.00); UPenn, 8.00(7.7-8.3)/0.80(0.75-0.84).

CONCLUSION

This study provides extensive multi-institutional validated evidence that machine learning tools can identify peritumoral neoplastic infiltration and predict location of future recurrence, by decrypting the MRI signal heterogeneity in peritumoral tissue. Our analyses leveraged the unique dataset of the ReSPOND consortium, which aims to develop and validate AI-based biomarkers for individualized prediction and prognostication and establish generalizability in a multi-institutional setting.

NIMG-29. ASSOCIATION OF PARTIAL T2-FLAIR MISMATCH SIGN AND ISOCITRATE DEHYDROGENASE MUTATION IN WHO GRADE 4 GLIOMA/GLIOBLASTOMA: RESULTS FROM THE RESPOND CONSORTIUM

PURPOSE

T2-FLAIR mismatch (T2FM) is a highly specific imaging biomarker for isocitrate dehydrogenase (IDH) mutation in low-grade gliomas. Previous T2FM studies are inconsistent for glioblastoma (GBM)/grade-4 glioma, partly due to low IDH-mutation prevalence in high-grade gliomas. We leveraged a large multi-institutional GBM/grade-4 glioma cohort to analyze the association of partial T2FM and IDH-mutation (T2-hyperintense, FLAIR-hypointense, nonenhancing, nonedema).

METHODS

We analyzed preoperative MRI of 1500 pathologically confirmed GBM/grade-4 gliomas with known IDH-mutation status from the ReSPOND consortium, consisting of the following institutions (sample size): Ivy GBM Atlas Project (33), Catalan Institute of Oncology (132), Case Western Reserve University/University Hospitals (132), New York University (55), Ohio State University (25), University of Pennsylvania (641), University Hospital Río Hortega (16), Yonsei University Health System (118), The Cancer Imaging Archive (93), Thomas Jefferson University (48), Tata Memorial Hospital (22), University of Pittsburgh Medical Center (156), and Washington University School of Medicine in St. Louis (57). Sequences were co-registered to a common anatomic atlas. Continuous variables were compared by t-test and categorical variables by Χ 2-test.

RESULTS

71 (4.7%) were IDH-mutants, significantly younger (43±1 v. 62±12 years, p=5x10-37), and more likely to exhibit partial T2FM (20% v. 0.4%, p=1x10-43), frontal lobe predominance (68% v. 29%, p=7x10-12), nonenhancing components (T2/FLAIR-intermediate signal, nonedema; 45% v. 9%, p=1x10-22), and cystic components (smooth margins, no/minimal enhancement, homogeneous FLAIR suppression; 17% v. 3%, p=7x10-11) than IDH-wildtypes. 20 cases had partial T2FM (14 IDH-mutant, 6 IDH-wildtype). Sensitivity of partial T2FM for IDH-mutation was 19.7%, specificity 99.6%, positive predictive value 70%, and negative predictive value 96.1%. Subset analysis of 983 IDH-wildtypes with known MGMT methylation status (406 MGMT-hypermethylated) showed frontal lobe predominance was more common in MGMT-hypermethylated than MGMT-unmethylated (39.4% v. 24.3%, p=.02); other imaging characteristics did not significantly differ.

CONCLUSIONS

Partial T2FM is a highly specific imaging biomarker for IDH-mutation in GBM/grade-4 glioma.

NIMG-33. PROGNOSTIC STRATIFICATION OF DE NOVO GLIOBLASTOMA PATIENTS ACROSS 22 GEOGRAPHICALLY DISTINCT INSTITUTIONS: UPDATES FROM THE RESPOND CONSORTIUM

PURPOSE

Glioblastoma, IDH-wildtype, is the most common primary malignant adult brain tumor with median overall survival (OS) of ~14 months, with little improvement over the last 20 years. We hypothesize that AI-based integration of quantitative tumor characteristics, independent of acquisition protocol and equipment, can reveal accurate generalizable prognostic stratification. We seek an AI-based OS predictor using routine clinically acquired MRI sequences, quantitatively evaluated across institutions of the ReSPOND (Radiomics Signatures for PrecisiON Diagnostics) consortium.

METHODS

We identified a retrospective cohort of 2,293 diffuse glioma (IDH-wildtype/-NOS/-NEC) patients from 22 geographically distinct institutions across 3 continents, with preoperative structural MRI scans. The entire tumor burden was automatically segmented into 3 sub-compartments, i.e., enhancing, necrotic, peritumoral T2-FLAIR abnormality. We developed our AI predictor by multivariate integration of i)patient age, ii)tumor sub-compartment volume normalized to brain volume, iii)spatial distribution characteristics (tumor location, distance to the ventricles, and laterality), and iv)morphologic descriptors (major axes’ length, axes’ ratio, extent, and number of tumors). The AI predictor returns a continuous value between 0-1, defining short-, intermediate-, and long-survivors based on thresholds on the 25th and 75th percentiles. Leave-One-Site-Out-Cross-Validation was used to assess the generalizability of our stratification. Kaplan-Meier survival curves were computed for OS analysis and evaluated by a Cox proportional hazards model for statistical significance and hazard ratios.

RESULTS

Survival analysis yielded a hazard ratio of 2.07 (95%CI, 2.06-2.08, p-value= 4.8e-102) for patient stratification into short-, intermediate-, and long-survivors. Pearson correlation between the predicted and actual OS yielded an R= 0.49.

CONCLUSION

Multivariate integration of visually quantified tumor characteristics, agnostic to acquisition protocol/equipment, yields an accurate OS surrogate index. Validation of our AI model in the largest centralized glioblastoma imaging dataset, from the ReSPOND consortium, supports its generalizability across diverse patient populations and acquisition settings, potentially contributing to equitable improvements of personalized patient care.

Dual ancestries and ecologies of the Late Glacial Palaeolithic in Britain

Genetic investigations of Upper Palaeolithic Europe have revealed a complex and transformative history of human population movements and ancestries, with evidence of several instances of genetic change across the European continent in the period following the Last Glacial Maximum (LGM). Concurrent with these genetic shifts, the post-LGM period is characterized by a series of significant climatic changes, population expansions and cultural diversification. Britain lies at the extreme northwest corner of post-LGM expansion and its earliest Late Glacial human occupation remains unclear. Here we present genetic data from Palaeolithic human individuals in the United Kingdom and the oldest human DNA thus far obtained from Britain or Ireland. We determine that a Late Upper Palaeolithic individual from Gough's Cave probably traced all its ancestry to Magdalenian-associated individuals closely related to those from sites such as El Mirón Cave, Spain, and Troisième Caverne in Goyet, Belgium. However, an individual from Kendrick's Cave shows no evidence of having ancestry related to the Gough’s Cave individual. Instead, the Kendrick’s Cave individual traces its ancestry to groups who expanded across Europe during the Late Glacial and are represented at sites such as Villabruna, Italy. Furthermore, the individuals differ not only in their genetic ancestry profiles but also in their mortuary practices and their diets and ecologies, as evidenced through stable isotope analyses. This finding mirrors patterns of dual genetic ancestry and admixture previously detected in Iberia but may suggest a more drastic genetic turnover in northwestern Europe than in the southwest.

The authors report genetic, archaeological and stable isotopic data from two late Palaeolithic individuals in Britain, from Gough's Cave and Kendrick's Cave. The individuals differ not only in their ancestry but also their diets, ecologies and mortuary practices, revealing diverse origins and lifeways among inhabitants of late Pleistocene Britain.

Genomes from a medieval mass burial show Ashkenazi-associated hereditary diseases pre-date the 12th century

We report genome sequence data from six individuals excavated from the base of a medieval well at a site in Norwich, UK. A revised radiocarbon analysis of the assemblage is consistent with these individuals being part of a historically attested episode of antisemitic violence on 6 February 1190 CE. We find that four of these individuals were closely related and all six have strong genetic affinities with modern Ashkenazi Jews. We identify four alleles associated with genetic disease in Ashkenazi Jewish populations and infer variation in pigmentation traits, including the presence of red hair. Simulations indicate that Ashkenazi-associated genetic disease alleles were already at appreciable frequencies, centuries earlier than previously hypothesized. These findings provide new insights into a significant historical crime, into Ashkenazi population history, and into the origins of genetic diseases associated with modern Jewish populations.

Gliocova: Predictors of Post-Operative Complications, 30 Day Mortality and Readmission After First Surgical Intervention in Brain Tumour Patients in England Between 2013-2018

AIMS

The Gliocova dataset uses linked English national cancer data on all 51,775 adult primary brain tumour patients diagnosed between 2013-2018. Here we investigate patient safety and post-operative complications after first surgical intervention.

METHOD

We identified patients undergoing first surgical intervention (surgical debulking or biopsy) and used a modified Delphi approach to identify diagnosis codes indicating potential post-surgical complications. We calculated Elixhauer Comorbidity Index (ECI) weights based on our data and developed regression models to link patient characteristics and ECI with 30-day mortality, readmission and chance of complication.

RESULTS

29,258 out of 51,775 patients underwent a surgical intervention (28,173 surgical debulking; and 1,207 biopsy). 11,959 (40.9\%) patients had at least one comorbidity during first intervention admission. In hospital mortality was 0.99\% (N = 289), 30-day mortality was 2.3\% (N = 677) and 30-day readmission was 12.7\% (N = 3,725). 13,137 patients (44.9\%) had at least one complication code from our defined list, either during their first surgical intervention or during a 30-day readmission. Predictors of 30-day mortality, readmission, and risk of complications included age, ECI score, number of complications, type of intervention (biopsy vs surgical debulking), income quintile, and tumour type (i.e., Glioblastoma versus other types of brain tumours).

CONCLUSION

To our knowledge this is the first study in England to assess post-surgical complications in a large brain tumour patient cohort. Our further work will focus on variation in outcomes between different centres/ centre volumes/ regions and the cost of complications. More information: https://blogs.imperial.ac.uk/gliocova/about-gliocova/.

P12.03 A Delphi survey to inform core ‘red flag’ symptoms for an electronic patient reported outcome system in glioblastoma follow up

BACKGROUND

Glioblastoma is a common and aggressive primary malignant brain tumour in adults associated with a poor prognosis and considerable symptom burden. Clinical review and serial neuroimaging remain the primary monitoring tools to assess for disease status. However, the evidence base for the existing surveillance imaging schedule is yet to be established. New models of follow up care are needed to demonstrate better patient outcomes in this patient cohort. There are indications that patient-reported outcome measures (PROMs) can contribute to improved survival and maintaining an optimal quality of life in other oncology populations.

MATERIALS AND METHODS

There are no standardised PROMs for the priority symptoms in glioblastoma patients, which can be used for evaluation in clinical care as a surrogate marker for disease progression. A broad set of symptoms were therefore initially identified in a targeted literature search and were further refined via Delphi methodology, with the aim to obtain consensus amongst a small expert panel involved in the care of glioblastoma patients. A three round Delphi email survey was conducted. Consensus was defined as 70% agreement.

RESULTS

Symptom and function constructs were assessed for relevance, relationship to disease and treatment, sensitivity to change, psychometric properties and patient acceptability. Consensus was reached on the red flag symptoms and symptom clusters to monitor, as well as the minimum severity thresholds needed to trigger an alert on an electronic symptom reporting system, which has been developed to allow patient self-reporting of symptoms during treatment.

CONCLUSION

The red flag symptoms to monitor, along with the symptom severity thresholds, informed an app-based symptom reporting system, which is currently being piloted in a feasibility study exploring triggered imaging using ePROMs. This has the potential to inform future clinical practice through development of patient reported biomarkers.

O15: DISRUPTION OF THE BLOOD-SPINAL CORD BARRIER PREDICTS PERMANENT PARAPLEGIA AFTER THORACOABDOMINAL AORTIC ANEURYSM REPAIR

Introduction

Paraplegia post-thoracoabdominal aortic aneurysm (TAAA) repair remains both a devastating and poorly understood complication. We related temporal changes in cellular and protein composition of cerebrospinal fluid (CSF) to neurological outcomes after TAAA repair to gain mechanistic insights driving paraplegia.

Method

Patients undergoing TAAA repair (open or endovascular) with a CSF drain were prospectively recruited between 2016-2018. CSF was collected pre-operatively and 24-hourly until removal. Daily neurological examinations were performed by blinded neurologists to the study. CSF cell content was characterised by flow cytometry and proteome analysed by tandem-mass-tag proteomics. An in-vivo rat model was modified using 15 minutes of aortic occlusion to produce consistent paraplegia. Rats were analysed neuro-behaviourally and histologically.

Result

CSF was analysed from 52 patients (age: 70.27+/-11.4; 66% male; open (n=9), endovascular (n=43)). 12 developed paraplegia of whom 5 remained permanently-paraplegic. Demographics were comparable between paraplegics, those who recovered and without post-op neurology. Permanent paraplegia was associated with a significant infiltration of CSF CD45+ leucocytes (P<0.0001). Levels of ADVS-1 was >3-fold higher in permanent-paraplegics CSF versus those who recovered (P=0.0008). ADVS-1 >15ng/ml predicted permanent paraplegia with 100% specificity. Pre-treatment with ADVS-1 inhibition significantly improved walking (<0.001) and increased astrocytic staining in the lateral corticospinal, reticulospinal and rubrospinal tracts versus controls (P=0.03, 0.04, 0.04 respectively).

Conclusion

Permanent paraplegia is associated with shedding of ADVS-1 from parenchymal cord into CSF and blood/spinal-cord barrier disruption leading to cord oedema/leucocyte infiltration. Pre-treatment with ADVS-1 inhibition led to neurobehavioural and histological improvements offering translational hope for this devastating complication.

Take-home message

ADVS-1 is a novel biomarker of paraplegia where accurate biomarkers have proven challenging but more importantly it has proven a therapeutic target with genuine translational potential.

Learning joint segmentation of tissues and brain lesions from task-specific hetero-modal domain-shifted datasets

Brain tissue segmentation from multimodal MRI is a key building block of many neuroimaging analysis pipelines. Established tissue segmentation approaches have, however, not been developed to cope with large anatomical changes resulting from pathology, such as white matter lesions or tumours, and often fail in these cases. In the meantime, with the advent of deep neural networks (DNNs), segmentation of brain lesions has matured significantly. However, few existing approaches allow for the joint segmentation of normal tissue and brain lesions. Developing a DNN for such a joint task is currently hampered by the fact that annotated datasets typically address only one specific task and rely on task-specific imaging protocols including a task-specific set of imaging modalities. In this work, we propose a novel approach to build a joint tissue and lesion segmentation model from aggregated task-specific hetero-modal domain-shifted and partially-annotated datasets. Starting from a variational formulation of the joint problem, we show how the expected risk can be decomposed and optimised empirically. We exploit an upper bound of the risk to deal with heterogeneous imaging modalities across datasets. To deal with potential domain shift, we integrated and tested three conventional techniques based on data augmentation, adversarial learning and pseudo-healthy generation. For each individual task, our joint approach reaches comparable performance to task-specific and fully-supervised models. The proposed framework is assessed on two different types of brain lesions: White matter lesions and gliomas. In the latter case, lacking a joint ground-truth for quantitative assessment purposes, we propose and use a novel clinically-relevant qualitative assessment methodology.

GliMR: Cross-Border Collaborations to Promote Advanced MRI Biomarkers for Glioma

Purpose

There is an annual incidence of 50,000 glioma cases in Europe. The optimal treatment strategy is highly personalised, depending on tumour type, grade, spatial localization, and the degree of tissue infiltration. In research settings, advanced magnetic resonance imaging (MRI) has shown great promise as a tool to inform personalised treatment decisions. However, the use of advanced MRI in clinical practice remains scarce due to the downstream effects of siloed glioma imaging research with limited representation of MRI specialists in established consortia; and the associated lack of available tools and expertise in clinical settings. These shortcomings delay the translation of scientific breakthroughs into novel treatment strategy. As a response we have developed the network “Glioma MR Imaging 2.0” (GliMR) which we present in this article.

Methods

GliMR aims to build a pan-European and multidisciplinary network of experts and accelerate the use of advanced MRI in glioma beyond the current “state-of-the-art” in glioma imaging. The Action Glioma MR Imaging 2.0 (GliMR) was granted funding by the European Cooperation in Science and Technology (COST) in June 2019.

Results

GliMR’s first grant period ran from September 2019 to April 2020, during which several meetings were held and projects were initiated, such as reviewing the current knowledge on advanced MRI; developing a General Data Protection Regulation (GDPR) compliant consent form; and setting up the website.

Conclusion

The Action overcomes the pre-existing limitations of glioma research and is funded until September 2023. New members will be accepted during its entire duration.

The problem with petrous? A consideration of the potential biases in the utilization of pars petrosa for ancient DNA analysis

Advances in NGS sequencing technologies, improved laboratory protocols and new bioinformatic workflows have seen huge increases in ancient DNA (aDNA) research on archaeological materials. A large proportion of aDNA work now utilizes the petrous portion of the temporal bone (pars petrosa), which is recognized as an excellent skeletal element for long-term ancient endogenous (host) DNA survival. This has been significant due to the often low endogenous content of other skeletal elements, meaning that large amounts of sequencing are frequently required to obtain sufficient genetic coverage. However, exclusive sampling of the petrous for aDNA analysis introduces a new set of potential biases into our scientific studies - and these issues are yet to be considered by ancient DNA researchers. This paper aims to outline the possible biases of utilizing petrous bones to undertake aDNA analyses and highlight how these complications may potentially be overcome in future research.

Erratum: The Beaker phenomenon and the genomic transformation of northwest Europe

This corrects the article DOI: 10.1038/nature25738.

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.

Think of the children: growing up with parents who have learning difficulties

This paper summarizes the findings of a research study that set out to explore how people who were brought up in a family headed by a parent or parents with learning difficulties managed the transition to adulthood. The authors focus on four key issues arising from their research: resilience in children, the notion of parental competence, the importance of family and the effects of social exclusion. Implications for policy and practice are also addressed.

An unusual case of pneumocephalus

The authors present an unusual cause of pneumocephalus in a previously fit and well female octogenarian who presented with acute onset altered level of consciousness and generalised weakness. Radiological imaging demonstrated widespread cerebritis with pneumocephalus and gas within the superior sagittal sinus. Blood culture grew Clostridium septicum, a virulent but rare organism that can infect normal tissues. The close association between C septicum and both haematological and bowel malignancies must be considered if this organism is cultured.

Automated variance reduction for MCNP using deterministic methods

In order to reduce the user's time and the computer time needed to solve deep penetration problems, an automated variance reduction capability has been developed for the MCNP Monte Carlo transport code. This new variance reduction capability developed for MCNP5 employs the PARTISN multigroup discrete ordinates code to generate mesh-based weight windows. The technique of using deterministic methods to generate importance maps has been widely used to increase the efficiency of deep penetration Monte Carlo calculations. The application of this method in MCNP uses the existing mesh-based weight window feature to translate the MCNP geometry into geometry suitable for PARTISN. The adjoint flux, which is calculated with PARTISN, is used to generate mesh-based weight windows for MCNP. Additionally, the MCNP source energy spectrum can be biased based on the adjoint energy spectrum at the source location. This method can also use angle-dependent weight windows.

Thermodynamic law for adaptation of plants to environmental temperatures

A thermodynamic law of adaptation of plants to temperature is developed. Plant growth rate is proportional to the product of the metabolic rate and the metabolic efficiency for production of anabolic products. Over much of the growth temperature range, metabolic rate is proportional to mean temperature and efficiency is proportional to the reciprocal of temperature variability. The mean temperature and short-term (hours to weeks) variability of temperature during the growth season at a particular location thus determine the optimum energy and growth strategy for plants. Because they can grow and reproduce most vigorously, plants with a growth rate vs. temperature curve that matches the time-at-temperature vs. temperature curve during the growth season are favored by natural selection. The law of temperature adaptation explains many recent and long-standing observations of plant growth and survival, including latitudinal gradients of plant diversity and species range.

Late onset seizures, hemiparesis and blindness in hemolytic uremic syndrome

Neurologic complications of hemolytic uremic syndrome, including seizures, usually occur early during the acute phase of the illness. We report a3-year-old girl with classic diarrhea-associated hemolytic uremic syndrome who developed late onset seizures, hemiparesis and transient blindness on the 17th hospital day, at which time her recovery was characterized by improvement in her blood pressure, serum electrolytes, renal function, hematocrit and platelet count. A CT and MR revealed brainstem and posterior parietal and occipital infarct/edema. The association of these radiologic findings within the posterior distribution along with visual loss and seizures are unique to posterior reversible encephalopathy syndrome. Within 7 days, she regained motor function and vision and had no further seizure activity. At 6 months follow-up, physical examination revealed normal motor function and vision and a repeat MR showed near resolution of the previous findings with minimal occipital lobe gliosis. This case report describes the uncommon finding of late onset seizures occurring during the recovery phase of hemolytic uremic syndrome with MR findings consistent with posterior reversible encephalopathy syndrome.

Is first trimester exposure to the combination of antiretroviral therapy and folate antagonists a risk factor for congenital abnormalities?

OBJECTIVES

To assess use of antiretroviral therapy (ART) by HIV positive pregnant women in London since 1994 and the risk of congenital abnormalities associated with multidrug exposure during the first trimester of pregnancy.

METHODS

Retrospective multicentre study of medical, obstetric, and paediatric notes of all mother-infant pairs, where the mother was known to be HIV infected before delivery, using a standardised proforma.

RESULTS

In this study of 195 mother-infant pairs, use of ART during any stage of pregnancy increased from 33.3% in 1994 to 92.5% in 1999 (p=0.01, trend). First trimester exposure increased from 0% in 1994 to 27.5% in 1999 (p=0.00045, trend). Congenital malformations were observed in nine infants (4.6%). Compared with infants not exposed to ART or folate antagonists during the first trimester (n=148), exposure to both ART and folate antagonists during the first trimester (n=13) was associated with an increased risk of congenital abnormalities (4% v 23.1%; OR 7.10, 95% CI 1.5, 34.2). No malformations were observed in the 34 children exposed to either ART or folate antagonists alone during the first trimester.

CONCLUSION

An increasing number of HIV infected women conceived while on ART. Although there is no evidence of teratogenicity caused by ART if given alone during the first trimester, exposure to the combination of ART and folate antagonists was associated with a significantly higher risk of congenital abnormalities in this cohort.

Congenital foregut duplication cysts of the anterior tongue

OBJECTIVE

To review our experience with foregut duplication cysts of the anterior tongue, an unusual and rarely encountered mass in this location.

DESIGN

A retrospective review of patients with anterior tongue foregut duplication cysts identified between 1990 and 2000.

SETTING

Academic, tertiary care children's medical center.

PATIENTS

Six pediatric patients (5 boys and 1 girl) ranging in age from birth to 8 months at diagnosis.

INTERVENTION

Three patients underwent preoperative magnetic resonance imaging (MRI). All 6 patients underwent excisional biopsy.

MAIN OUTCOME MEASURES

Clinical description of foregut duplication cysts, ability to make the diagnosis preoperatively, and recurrence rates.

RESULTS

No patient presented with respiratory compromise, despite the large size of the anterior tongue masses (range, 1.5-2.4 cm). An MRI study was performed in 3 patients, all given a presumptive diagnosis of dermoid cyst based on the radiographic findings. No patient was diagnosed correctly prior to surgical excision. All patients underwent surgical excision, and the average time from birth to surgical excision was 11 months (range, 3 days to 3.7 years). Surgical pathologic findings were reported as a foregut duplication cyst (enterocystoma) in all patients, with 3 specimens containing foci of gastric mucosa. No recurrence has occurred at 1-month follow-up.

CONCLUSIONS

Foregut duplication cysts rarely present in the anterior tongue and are easily misdiagnosed preoperatively. An MRI study is helpful in preoperative planning, although all lesions were radiologically indistinguishable from dermoid cysts. These masses may be an underappreciated entity in the differential diagnosis of congenital anterior tongue masses.

The use of gated cine phase contrast and MR venography in achondroplasia

OBJECTS

Foramen magnum and jugular foramen stenosis, well-known problems in achondroplasia, may result in brain stem compression and venous outflow obstruction, respectively. We studied a series of children with achondroplasia using gated cine phase contrast (PC) CSF flow studies to evaluate CSF dynamics across the foramen magnum and MR venography (MRV) to depict obstructed venous drainage.

METHODS

Ten patients (9 months to 11 years, mean 2.85 years) were referred for possible brain stem compression. MRI included routine sequences, cine PC with velocity encoding (VENC) = 5 cm/s, and MRV. Six patients, including the asymptomatic patient, had brain stem compression without tonsillar herniation; two had tonsillar herniation; and two had neither brain stem compression nor tonsillar herniation. Abnormal tonsillar movement was seen only with tonsillar herniation. MRV showed steno-occlusive disease of the internal jugular vein (IJV) in nine patients, sigmoid sinus in four, and absent or hypoplastic transverse sinus in seven. Veno-occlusive disease was not progressive. No patient had massive hydrocephalus, although larger ventricles were associated with more profuse venous collateral formation and more severe degrees of IJV stenosis. Three patients have undergone CSF diversion.

CONCLUSIONS

MR imaging may be useful in defining the pathophysiology of brain stem compression and hydrocephalus in achondroplasia.

MR venography in children with complex craniosynostosis

PURPOSE

Chronic venous hypertension due to jugular foramen stenosis has been proposed as an etiology for the hydrocephalus and tonsillar herniation seen in some patients with complex craniosynostosis. We report the use of MR venography (MRV) to evaluate venous outflow obstruction in this clinical setting.

MATERIALS AND METHODS

We studied 17 patients, (ages 4 months to 34 years; mean 7.3 years) with complex craniosynostosis; 8 patients with Crouzon's syndrome, 2 with Apert's, 1 with Pfeiffer's and 6 patients without an eponymous classification. MR imaging included routine imaging sequences and axial 2D TOF MRV. Patterns of venous drainage and the presence of hydrocephalus and tonsillar herniation were noted.

RESULTS

Jugular vein obstruction was seen in 12/17 patients; in 5/8 patients with Crouzon's, 1/2 with Apert's, the single patient with Pfeiffer's and 5/6 patients with nonsyndromic craniosynostosis. The predominant collateral drainage was via the posterior condylar veins. Nine of 12 (75%) of the patients with abnormal MRV had hydrocephalus; 3/8 patients with Crouzon's, 1/2 patients with Apert's, and 5/6 nonsyndromic patients. Two patients had hydrocephalus with normal MRV. Ten patients had tonsillar herniation, which was associated with shunted hydrocephalus in 7/10 patients, and hydrocephalus seen prior to shunt placement in 3/9. Nine of 10 patients with tonsillar herniation had an abnormal MRV, while 1 patient had a normal MRV. Venous pressures measured in 1 patient showed an 8-mm-Hg differential across the skull base.

CONCLUSIONS

The posterior condylar veins appear pivotal in maintaining venous drainage when the jugular bulbs are occluded. Although the association between venous outflow obstruction, hydrocephalus and tonsillar herniation is intriguing, evidence of venous outflow obstruction by MRV may not be indicative of significant intracranial venous hypertension.

Velogenic Newcastle disease in imported caged birds

Velogenic Newcastle disease was diagnosed in pet birds intended for importation into Canada. Virological and histopathological examination confirmed the presence of the disease. The group of birds was denied entry into Canada. Similar birds illegally imported are a potential source of velogenic Newcastle disease virus and are a threat to domestic poultry.

Idiopathic ischemic cerebral infarction in childhood: depiction of arterial abnormalities by MR angiography and catheter angiography

BACKGROUND AND PURPOSE

We report our experience with MR imaging, MR angiography, and catheter angiography in children with acute idiopathic cerebral infarction and suggest that catheter angiography may still play an important role in this setting.

METHODS

During the past 8 years, 18 children with idiopathic cerebral infarction underwent MR imaging and catheter angiography; 17 were also studied with MR angiography. MR imaging was done within 34 hours after onset of hemiplegia or seizures or both. Sixteen patients underwent catheter angiography within 36 hours of MR imaging; 12 studies were performed within 22 hours. Two patients underwent catheter angiography, in both cases within 72 hours. Infarcts were compared with arterial abnormalities seen at catheter angiography, and the results of MR angiography were compared with those seen at catheter angiography.

RESULTS

Comparing MR angiography with catheter angiography, we found the positive predictive value of MR angiography for arteriopathy was 100%, with a negative predictive value of 88%. MR angiography was equivalent to catheter angiography in the detection and depiction of proximal middle cerebral artery disease; however, depiction of disease in the internal carotid artery (ICA) and detection of peripheral embolic disease were better with catheter angiography than MR angiography.

CONCLUSION

Basal ganglia lesions associated with ICA disease by MR angiography should probably be studied with digital subtraction angiography, as MR angiography did not depict the length and severity of ICA disease as well as catheter angiography did. Hemispheric infarcts should be studied with catheter angiography, as emboli may occur in the absence of heart disease; the circle of Willis may be uninvolved with embolic disease, and MR angiography is not sensitive to emboli in small peripheral intracranial arteries.

Against the odds: growing up with parents who have learning difficulties

For this article we drew on material from a study in which we explored how people who were brought up in a family headed by a parent or parents with learning difficulties managed the transition to adulthood. Using evidence from in-depth interviews, we provided an assessment of how the now-adult children came through what would generally be seen as a risk-filled upbringing. Despite the problems they encountered in their childhood, many of which originated outside the home, most of the informants had maintained a valued relationship with their family and remained close to their mother.

Specific interactions between human integrin alpha v beta 3 and chimeric hepatitis B virus core particles bearing the receptor-binding epitope of foot-and-mouth disease virus

Purified integrin alpha v beta 3 was used in solid-phase binding studies with chimeric hepatitis B cores which carry the RGD-containing loop of VP1 protein of the foot-and-mouth disease virus (FMDV). High levels of specific binding between the integrin and the particles were detected by enzyme-linked immunosorbent assays. The binding was Mn2+ cation dependent and could be competed with fibronectin, vitronectin, and the peptide GRGDSPK. Particles in which the RGD motif had been mutated to RGE failed to bind, indicating that the chimeric cores bound specifically to the ligand binding site of integrin alpha v beta 3. Electron micrographs showed several individual alpha v beta 3 molecules bound to the surface of each chimeric particle. Collectively, these data constitute firm evidence that the RGD-containing loop of FMDV is critical for binding to alpha v beta 3 and provide support for identification of alpha v beta 3 as a potential cellular receptor for FMDV.

Pollen deposition in the boreal forest of west-central Canada

Deposition of tree and tall shrub pollen was examined along a 5.5-km transect in mixed boreal forest in west-central Manitoba, Canada. Annual pollen deposition averaged ca. 6850 grains/cm2 in 1992, with jack pine contributing 67.3% and spruce 24.5% of the total. In general, flowering plant species released their pollen in early to late May, while conifer (spruce and pine) pollen release occurred in early to mid-June. Pollen deposition was poorly correlated with relative species abundance in the community, with some species (e.g., jack pine) being over-represented in the pollen rain and others (e.g., aspen poplar) being under-represented. In 1993, spruce pollen deposition was 63% of that in 1992. By contrast, total pollen deposition by jack pine showed little variation from 1991 to 1993. However, pollen release dates varied between years, occurring earlier in years with warmer spring temperatures. Jack pine pollen release exhibited diurnal variation, with the majority of pollen being released during daylight hours on warm, sunny days. Keywords: Manitoba, jack pine, black spruce, boreal forest, pollen rain, palynology.